head to head
Sniper Elite III asks more than Zombie Army Trilogy, and the gap is optimization.

Execution · Practiced Mastery
Plannable stealth routing punctuated by precise ballistic marksmanship.

Execution · Practiced Mastery
A co-op horde shooter testing sniper aim and chokepoint planning against scripted waves.
Sniper Elite III leans Execution (Practiced Mastery); Zombie Army Trilogy leans Execution (Practiced Mastery).
Same score on execution - which means the number cannot separate them. The difference is in what each one asks of you.
Sniper Elite III
Ballistic long shots demand steady, compensated aim
Zombie Army Trilogy
Long-range sniping and horde kiting demand steady aim
Sniper Elite III leans a little harder on reads, though the gap is small.
Sniper Elite III
Enemy AI follows mappable alert and search routines
Zombie Army Trilogy
Undead waves follow predictable spawn scripts
Same score on variance - which means the number cannot separate them. The difference is in what each one asks of you.
Sniper Elite III
Patrol details and wind vary slightly per attempt
Zombie Army Trilogy
Spawn timing varies a little between runs
Sniper Elite III leans clearly harder on optimization.
Sniper Elite III
Open maps reward planned routes, sound masking and relocation
Zombie Army Trilogy
Choke points, trap placement and ammo economy reward planning
A matching score does not mean a matching test. Two games can both sit at 10 on execution and demand completely different things of you - which is why the reasoning above matters more than the number beside it.